An apparatus of this type is disclosed in U.S. Pat. No. 4,785,441. In this known apparatus errors in the tracking signal, the errors being caused by tilting of the optical recording medium or by different pit depths in the optical recording medium, are compensated for by the delay times of the variable delay elements being altered on the basis of a phase comparison carried out during operation.
The known apparatus may be regarded as having the disadvantage that although errors caused by tilting of the optical recording medium or by different pit depths of the optical recording medium can be compensated for relatively well, the way in which an error caused by lens displacement is detected is not optimal. This is due to the fact that error components are included from other error sources, for example changes in the component properties which are caused by ageing or changing ambient conditions. The result of this is that the compensation is indeed not optimal.